Studies will continue on apsects of gene regulation and evolution in certain insect systems, with special attention to the vitellins and vitellogenins. One major area of work is the mode of action of juvenile hormone in controlling vitellogenin synthesis in the fat body adult female Locusta migratoria, including cytoplasmic hormone receptors and changes in gene replication and transcription. A second area is the structures of insect vitellins and vitellogenins, with a view to elucidating evolutionary relationships among this group of proteins. Other aspects of regulatory and developmental biochemistry of insects may also receive attention.